Flooder refrigerant condenser systems

ABSTRACT

An arrangement for a condenser especially well adapted for use in mechanical refrigeration systems of the conventional type. The normal compressor superheated refrigerant gas discharge is fed into liquid refrigerant from a bottom region of the condenser. The complete condenser surface to the level of the refrigerant liquid is thus maintained at an elevated and uniform temperature.

Unlted States Patent 1 1 1111 3,922,880

Morris Dec. 2, 1975 FLOODER REFRIGERANT CONDENSER 3.266.267 8/1966 Merrick ct al. 62/476 SYSTEMS FOREIGN PATENTS OR APPLICATIONS [76] Inventor: Herman H. Morris, PO. Box 3129, 549,359 2/1923 France 11 62/506 Chattanooga, Tenn. 37404 Primary Examiner-William F. ODea [22] Flled' 1974 Assistant Examiner-Peter D. Ferguson [21] Appl. No.: 449,734 Attorney, Agent, or Firm-Hill, Gross, Simpson, Van

Santen, Steadman, Chiara & Simpson [52] US. Cl. 62/498; 62/506; 62/507;

261/140 A; 261/153 [57] ABSTRACT 15 1 Int. c1. F25B 1/00 Arr arrangement for a Condenser especially well 58 Field of Search 62/115, 119, 121, 49s, adaPted for use in mechanical refrigeration systems of 52 50 507, 261/140, 140 A, 153, 156 the conventional type. The normal compressor superheated refrigerant gas discharge is fed into liquid re- [56] References Cited frigerant from a bottom region of the condenser. The

UNITED STATES PATENTS complete condenser surface to the level of the refrigl 533 336 4/1925 P N 62606 X erant liquid is thus maintained at an elevated and uniowna 1,751,209 3/1930 Kucher 62/506 x form temperature 3,038,316 6/1962 Bourne 62/484 X 11 Claims, 7 Drawing Figures El L.

III

US. Patent Dec. 2, 1975 'Sheet20f2 -3,922,880

FLOODER REFRIGERANT CONDENSER SYSTEMS BACKGROUND OF THE INVENTION In the art of refrigeration condensers and, especially mechanical refrigeration systems of the vapor compression type, it has heretofore been conventional to supply the hot gas from the compressor to the top or side of an air cooled condenser and to the top of a water cooled condenser.

For example, in such a refrigeration system employing an air cooled condenser, the normal compressor discharge is a superheated refrigerant gas which is discharged into such air cooled condenser and condensed within the condenser tubes in a gas (refrigerant) to gas (air) heat exchange. At a design ambient temperature of 95F and a compressor discharge pressure of 169.1 psig (Freon-l2), the compressor saturation discharge temperature is about 125F. Depending upon load conditions, the compressor refrigerant discharge temperature is superheated to a temperature ranging from about 110F to 135F.

The heat transfer in the condenser is gas to gas, and, at the condenser inlet, because of the temperature differential (in this example, 135F gas to 95F air), the heat exchange is good. Normally, the refrigerant is condensed and sub-cooled in the air cooled condenser to, say, about llO F. In this conventional operation, the temperature gradient of 135F to 110F across the air cooled condenser coil leaves the portion of the condenser coil opposite the hot gas inlet operating at a much reduced efficiency level relative to the condenser inlet because of the reduced temperature differential between the ambient air (95F) and the refrigerant gas, and refrigerant droplets, as the refrigerant in the condenser approaches the 1 F sub-cooled temperature.

Thus, in prior art refrigeration condenser arrangements, low and non-uniform temperature differentials are common on condenser surfaces and heat transfer efficiency is generally inefficient whether such are air cooled or water cooled.

BRIEF SUMMARY OF THE INVENTION The present invention relates to a method and an apparatus which enables one to operate a refrigeration condenser with improved efficiency in a mechanical refrigeration system of the vapor compression type.

By the present invention, hot compressed gaseous refrigerant in a refrigeration cycle is supplied directly into condensed, liquified refrigerant in a condenser. The invention achieves improved operating efficiency by direct heat transfer between the refrigerant liquid and the heat exchange fluid medium (e.g., from a liquid to air in the case of an air cooled condenser, and from liquid to liquid in the case of a water cooled condenser). The invention additionally allows maintenance of a uniform temperature at near refrigerant compressor discharge saturation temperatures across all the heat exchange surfaces of a condenser means up to the refrigerant liquid level in the coils or tubes thereof, in either an air cooled condenser or a water cooled condenser. Further, the invention permits a condenser means to act as a refrigerant liquid receiver.

BRIEF DESCRIPTION OF DRAWINGS In the drawings:

2 FIG. 1 is a diagrammatic representation of the basic refrigeration cycle as adapted for use in one embodiment of the present invention;

FIG. 2 is a vertical sectional view of the air cooled condenser assembly employed in the embodiment of FIG. 1, some parts thereof being shown in side elevation;

FIG. 3 is a vertical transverse sectional view taken along the line IIIIII of FIG. 2;

FIG. 4 is a fragmentary sectional view of the region of the inlet of the structure shown in FIG. 2 illustrating the practice of the present invention;

FIG. 5 is a view similar to FIG. 2 but showing as an alternative embodiment a water cooled condenser assembly employed in the embodiment of FIG. 1;

FIG. 6 is a view similar to FIG. 3 but taken along the line VI-VI of FIG. 5; and

FIG. 7 is a fragmentary view in vertical section through the discharge nozzle means of an alternative embodiment of the water cooled condenser assembly of FIG. 5.

DETAILED DESCRIPTION Referring to FIG. 1 there is seen the basic refrigeration cycle being used in a single stage vapor compression system herein designated in its entirety by the numeral 10. System 10 employs four basic components, a compressor 1 1, and a condenser 12, an expansion valve 13 and an evaporator 14. The system utilizes two pressures, high and low, as indicated in FIG. 1, to enable a continuous process to produce a cooling effect (low pressure is above, high pressure below line).

As liquid refrigerant flows through evaporator 14, heat is absorbed from a fluid being cooled and the refrigerant boils. The low pressure vapor from evaporator 14 passes to compressor 11 and is compressed. The pressure and temperature levels of the refrigerant in compressor 11 are increased to a point where the resulting superheated refrigerant vapor can be condensed by the cooling media available, here air about condenser 12. In compressing the refrigerant gas, heat of compression is added to vapor as the pressure is raised. The vapor then flows to the condensor 12 where the gas is liquified. The liquid refrigerant flows from the condenser 12 to the expansion valve 13 where its pressure and temperature are reduced to those in the evaporator 14, the cycle is thus completed. Those skilled in the art will appreciate that refrigeration cycles can be analyzed by means of a Mollier diagram or pressureenthalpy chart.

In system 10 hot gas discharge from compressor 1 l is fed to condensor 12 through conduit 16. Conduit l6 interconnects with an input pipe 17 through a coupling 18. The input pipe 17 acts as a supply tube for condenser l2 and extends horizontally across the bottom of condenser 12 generally concentrically through a reservoir tube 19. The input pipe 17 is provided with a plurality of perforations 21 through which compressed superheated gaseous material from compressor 11 escapes and enters the interior of the reservoir tube 19.

A plurality of elongated tubular conduits 22 in generally spaced parallel relationship to each other -extend upwardly from the reservoir tube 19 and communicate therewith. A header tube 23 extends across the upper ends of conduits 22 and is functionally interconnected with individual respective ends of the conduits 22 so that a common chamber is thus defined in the header tube 23 for the individual conduits 22. The interior of the reservoir tube 19 also acts as a common chamber for the conduits 22 at their respective lower end portions. In condenser 12 the terminal end of the supply tube 17 is closed by means of a pipe cap 24 and the input pipe 17 is maintained in fluid-tight relationship relative to reservoir tube 19 by means of an end cap support 26 at one end of the reservoir tube 19 and by end cap 27 at the opposite end thereof.

A gaseous refrigerant escaping through perforations 21 enters conduits 22 through the lower end portions thereof opening into reservoir tube 19. To improve the heat exchange capacity of condenser 12, such is provided with a plurality of cooling fins 28 each of which is in a flattened sheet-like form extending transversely across and about the conduits 22, the cooling fins 28 being generally in spaced parallel relationship to one another. The header tube 23 is sealed at its respective opposite end portions by means of a pair of end caps 30 so as to define a fluid-tight chamber therewithin. Refrigerant gas which is not condensed but escapes into upper portions of the condenser 12 including upper ends of the respective conduits 22 and the interior of header 23 is maintained at an internal pressure which is approximately equal to the pressure of gas entering the condenser 12 through conduit 16 by means of some sort of pressure equalization means. The pressure equalization means extends between a gravitationally top portion of the condenser 12 and a position along the input conduit 16 which is above a predetermined refrigerant condensate level in the conduits 22 of condenser 12. In the embodiment shown the pressure equalization means is provided by a capillary tube 29 through any convenient such means may be employed. Preferably this position is above condenser 12.

Within condenser 12 the level of refrigerant condensate (typically a saturated solution of condensed refrigerant containing dissolved gaseous refrigerant) is maintained in some predetermined configuration or height within the individual tubes 22; thus, the complete condenser surface up to the level of the refrigerant liquid is maintained at an elevated and uniform temperature so that a uniform temperature differential is maintained in the condenser 12 between air and liquid. In condenser 12 the conduits 22 are arranged in the form of two rows, each row being transversely spaced relative to the other, each individual row being generally parallel to the axis of the reservoir tube 19 and the header 23, t produce an efficient heat exchange.

Liquid condensed refrigerant is taken off from the condenser 12 through output pipe 31 which conveys liquid refrigerant to the expansion valve 13, as in system 10.

As those skilled in the art will appreciate, in place of the air cooled condenser 12, one may employ a water cooled condenser, such as condenser 33 of FIGS. and 6. Here, superheated compressed refrigerant gas is charged from an input conduit 34 into the bottom portion gravitationally speaking of a chamber 36 defined by a shell 37 and a pair of headers 38 and 39.

Header 39 has an internal chamber 41 and header 38 has a pair of internal chambers 42 and 43, respectively. A plurality of tubes 44 in generally spaced parallel relationship to one another transversely extend through the chamber 36 between the headers 38 and 39. Approximately one half of the tubes 44 extend between and communicate with respective chambers 42 and 41, while the other remaining tubes 44 extend between the chamber 41 and chamber 43, respectively. Cooling water is charged to chamber 42 via pipe 46 and passes through tubes 44 into chamber 41 and from chamber 41 back through tubes 44 and into chamber 43 finally exiting from the header 38 through pipe 47. In this way, gas entering the chamber 36 through conduit 34 is brought into heat exchange relationship with the outside surface portions of the tubes 44, so that as the gas escapes into the chamber 36 and expands therein it is condensed, as desired. Entering gas passes upwardly into the chamber 36 through and into a refrigerant condensate liquid maintained in the chamber 36 to some predesired level thereby to maintain a uniform temperature differential for heat exchange purposes in the chamber 36 as is accomplished, for example, in condenser 12. Liquified refrigerant is removed from chamber 36 at a bottom portion thereof through a tube 46, the tube 46 conveniently conveying the condensate to an expansion valve such as valve 13 in system 10. Pressure between the interior upper portion of chamber 36 and input conduit 34 is equalized by means of an interconnecting capillary tube 47, the capillary tube 47 interconnecting with the input conduit 34 at a position which is above a predetermined refrigerant fluid level in the chamber 36, as those skilled in the art will appreciate.

Header 39 is conveniently formed by means of a cupshaped member 47 and a base plate 48, member 47 being secured to plate 48 by means of nut and bolt assemblies 49 and sealing means (not shown). Similarly header 38 is conveniently formed by a pair of mating members 51 and 52 which are conveniently secured together by means of nut and bolt assemblies 53 and sealing means (not shown).

Those skilled in the art will appreciate that in a system 10, one may employ conventional compressor 11, expansion valve 13, and evaporator 14, respective assemblies. Also, those skilled in the art will appreciate that the present invention can be utilized not only in a single stage refrigeration cycle, such as is shown, for example, in FIG. 1, but also may be used in a centrifugal refrigeration system and in multi-stage refrigeration cycles (including compound and 'cascade). The condenser system of this invention is compatible with vari-' ous compressor assemblies including dynamic type centrifugal compressors and positive displacement type reciprocating compressors and the like. Those skilled in the art will appreciate that the capacity of a given condenser embodiment of the present invention is affected by mechanical design factors as well as application factors.

From the preceding discussion it will be appreciated that the present surface condenser assemblies of the present invention characteristically incorporate a fluidtight housing which has therein an interior chamber portion adapted to be located spatially in a gravitationally bottom portion of the housing when the condenser assembly incorporating such housing is functional and functioning. The housing is equipped with input port means and output port means located in such bottom region in laterally spaced relationship.

The housing is equipped with wall member portions which are adapted to be located spatially above the interior chamber portion when the incorporating condenser assembly is functional and functioning; Such wall members are adapted for heat transfer therethrough when a heat exchange fluid contacts outer surfaces thereof relative to interior portions of the housing. [n' the case of condenser 12 the housing is comprised of reservoir tube 19, conduit 22 and header 23 and the wall member portions are formed by the conduits 22 primarily. In the case of condenser 33 the housing is defined by the walls of chamber 36 as above described and the wall member portions are defined by the tubes 44, all as those skilled in the art will appreciate. Many different arrangements for a condenser assembly of the present invention are possible and practical and the illustrative examples provided herein are not intended to delimit the invention, particularly as from an apparatus viewpoint.

As those skilled in the art will appreciate, any convenient arrangement for the hot gas discharge nozzle means may be employed in a condenser assembly of this invention depending upon system design factors, such as desirable pressure loss through a given nozzle means. In general design criteria take into account and- /or are a function of hot gas pressure drop across orifices or nozzles, and of the sub-cooling effect or temperature depression below saturated discharge temperature of a given liquid refrigerant. For example, in place of the arrangement illustrated in FIG. 5, one may employ a hot gas discharge nozzle means having or producing a sub-cooling effect, such as the nozzle means illustrated in FIG. 7. Thus, in the arrangement shown in FIG. 7 a hot gas refrigerant conduit 51 conducts hot, gaseous refrigerant to a nozzle 52 situated across the mouth of a well 53 located in the bottom of a shell 37 of a condenser 33' which is otherwise similar to condenser 33. During operation of condenser 33 subcooled liquid refrigerant collects in well 53 and is conducted away through conduit 54.

In addition to its apparatus aspects, the present invention is further concerned with process aspects; thus, the present invention provides an improved condensation process for handling compressed superheated gaseous refrigerant with a surface condenser in a mechanical refrigeration system of the vapor compression type. One charges a superheated refrigerant gas discharge from a compression zone into a condensation zone. The superheated refrigerant gas is bottom fed into a liquid refrigerant condensate maintained at least in a'bottom region of the condensation zone. The level of condensate maintained in the condensation zone is variable, being dependent upon the needs and desires met in a particular use situation, as those skilled in the art will appreciate. When applied to the basic refrigeration cycle, the process of the present invention involves the steps of first passing a liquid refrigerant through an evaporation zone in which heat is absorbed from a fluid being cooled in the evaporation zone causing the liquid refrigerant to boil simultaneously. Next, the vaporized refrigerant is compressed in a compression zone with superheating. Thereafter, the superheated refrigerant gas discharge from the compression zone is fed to a condensation zone of the present invention, such discharge being fed into the liquid refrigerant in the condensation zone in a bottom region of the condensation 5 the evaporation zone.

. EMBODIMENTS The present invention is further illustrated by reference to the following Examples. Those skilled in the art 10 will appreciate that other and further embodiments are obvious and within the spirit and scope of this invention from the teachings of these present Examples taken with the accompanying specification and drawings.

EXAMPLES 1 THROUGH 3 A test condenser is constructed of bare copper tubing and consists of four 1 inch diameter, and two 1 inch diameter vertical copper tubes, 6 feet 6 inches in length, connected to top and bottom headers of 2 /8 inch diameter copper tubing each 2 feet 8 inches in length. The effective bare surface area of this test condenser is approximately 20 sq. ft. The compressor is a Carrier 5F30 at approximately 1,200 RPM. The completed refrigeration system develops approximately 5 tons capacity.

The head pressure is varied by the amount of city water piped in k inch pipe along the top condenser header. The city water pipe has holes to distribute water along top of such header.

The test thermometer wells consist of inch diameter copper pipe soldered into condenser outside vertical tube at 15 inches, 42 inches and 72 inches, respectively, from the bottom header, and into the center section of top and bottom headers. Each well is filled with oil.

Example 1 is observed with a charge of refrigerant filling the condenser tubes to approximately 12 inches from top of condenser. In Example 2 the refrigerant is removed from the condenser to the point of only clear- 40 ing a sight glass in liquid line to cooling coil leaving only a minimum amount of liquid in condenser. In Example 3 the refrigerant is added to the condenser to fill the tubes to the top condenser header. The flooded condenser system is not a critically charged system, but

more effective heat transfer occurs with the liquid in the condenser tubes.

The Examples 1 through 3 are observed without change in water over condenser and without appreciable change in inside load conditions.

It is noted that the bottom condenser header where the refrigerant hot gas is introduced to the condenser is at a lower temperature relative to the remainder of the condenser surface. This drop is caused by the hot gas jet action momentarily evaporating. refrigerant around the outside of the hot gas distributing nozzle and within the bottom condenser header. Results are recorded in Table 1 below.

Table 1 Example No. Variable Units 1 2 3 Compressor Discharge Pressure psig 200 215 205 Saturation Discharge Temperature F l37 M4 139 Compressor Discharge Temperature (Well in top header) "F 129 137 129% Condenser Tube Temperature,

Bottom Well "F 129 137% 123% Condenser Tube Temperature Center Well "F I29% 137% I25 Table l-continued Example No. Variable Units 1 2 3 Condenser Tube Temperature,

Top Well F l29 134 125% Condenser Bottom Header Temperature (Well) F H95; 124 ll9'k Suction Temperature (Well) F 49% 49 49 Suction Pressure psig 44 42 44 I claim:

1. A condenser assembly adapted for use in a mechanical refrigeration system of the vapor compression type comprising:

a fluid tight housing means having defined therein an interior chamber portion adapted to be located in a gravitationally bottom region of said housing,

input port means and output port means located in said bottom region in laterally spaced relationship,

wall member portions adapted to be located above said interior chamber portion, said wall members being adapted for heat transfer therethrough when a heat exchange fluid contacts outer surfaces thereof relative to interior portions of said housing means;

an input conduit associated with said input port means and adapted to extend thereto from a position located above a predetermined fluid level in said housing when said condenser assembly is functioning; and

pressure equalization means extending between a gravitationally top region of said housing and said input conduit at said position, said pressure equalization means comprising a capillary tube.

2. The condenser assembly of claim 1 wherein said wall member portions are affixed to outer wall regions of said housing means and comprise a plurality of elongated conduit means in spaced-apart relationship to each other adapted to extend generally normally to and outwardly from said interior chamber portion to interconnection with a second interior chamber portion located in and comprising said top region.

3. The condenser assembly of claim 1 wherein said wall member portions comprise a plurality of tubular members in spaced relationship to each other and to outer wall regions of said housing means, said tubular members extending through said housing means interiorly thereof and adapted to convey therethrough said heat exchange fluid.

4. The condenser assembly of claim 1 wherein said wall members extend vertically.

5. The condenser assembly of claim 1 wherein said wall members extend horizontally.

6. An air cooled condenser assembly adapted for use in a mechanical refrigeration system of the vapor compression type comprising A. a plurality of elongated conduit means in spaced relationship to each other, each adapted for heat transfer through side wall portions thereof,

B. a pair of header means each one at a different opposed respective end portion of said plurality of conduit means and functionally interconnecting individual respective ends of said conduit,

C. a distributor conduit extending through one of said header means, said conduit being perforated along its side walls and being in sealed engagement with the associated said header means at opposite ends thereof, one end of said distributor conduit defining an input port,

D. an input conduit associated with said input port and adapted to extend thereto from a position located above a predetermined fluid level in said housing when said condenser assembly is functioning and said distributor conduit is in a gravitationally bottom region of said condenser assembly,

E. pressure equalization means functionally extending between a gravitationally top region of said housing when said condenser assembly is functioning and said input conduit at said position, and

F. output port means located in said associated said header means.

7. A condenser assembly adapted for use in a mechanical refrigeration system of the vapor compression type, comprising:

a fluid-tight housing means having defined therein an interior refrigerant chamber portion having gravitationally bottom and top regions;

input port means and output port means located in said bottom region of said chamber; and

wall member portions adapted for heat exchange therethrough when a heat-sink fluid contacts surfaces of said wall members opposite other surfaces contacting refrigerant communicating with said chamber;

an input conduit communicating with said input port means and adapted to extend thereto from a position located above an operating fluid level in said housing; and a capillary tube constituting a pressure equalization means communicating with top region of said housing to said input conduit at said position. 8. A condenser assembly as defined in claim 7, further defined by:

said input port means comprising:

surfaces defining an open well in said bottom portion of said housing, a nozzle situated at the opening of the well and directed into the refrigerant chamber, and said compressed gaseous refrigerant passing through said nozzle, thereby to be sub-cooled; and

said output port means comprising a conduit com-,

municating with said input port well at a point gravitationally beneath said well opening. 9. A condenser assembly as defined in claim 7, wherein:

said heat-sink fluid comprises a gas such as air; said refrigerant chamber comprises a pair of header portions; and

9 said wall members define a plurality of elongate conduits having exteriors which contact said gas and interiors which communicate at opposite ends thereof with said refrigerant chamber headers and confine and carry said refrigerant in vapor and liquid forms. 10. A condenser assembly as defined in claim 7, wherein:

said heat-sink fluid comprises a liquid such as water;

and said wall members define a plurality of elongate conduits extending through said refrigerant chamber and separating said refrigerant vapor and liquid on an exterior thereof and the interior thereof carrying said heat-sink liquid. 11. An air cooled condenser assembly adapted for use in a mechanical refrigeration system of the vapor compression type, comprising:

a plurality of elongate conduit means in spaced relationship to each other, each adapted for heat transfer through side wall portions thereof;

first and second header means each at a different opposed respective end portion of said plurality of conduit means and interconnecting individual respective endstof said conduits;

a distributor conduit extending into said first header means, said conduit being perforated along its side walls in a gravitationally bottom region of said condenser assembly and being in sealed engagement with said first header means;

an input conduit communicating with said distributor conduit and adapted to extend thereto from a position located above a predetermined fluidlevel to said housing;

pressure equalization means extending between a gravitationally top region of said second header means and said input conduit at said position; and

output port means. 

1. A condenser assembly adapted for use in a mechanical refrigeration system of the vapor compression type comprising: a fluid tight housing means having defined therein an interior chamber portion adapted to be located in a gravitationally bottom region of said housing, input port means and output port means located in said bottom region in laterally spaced relationship, wall member portions adapted to be located above said interior chamber portion, said wall members being adapted for heat transfer therethrough when a heat exchange fluid contacts outer surfaces thereof relative to interior portions of said housing means; an input conduit associated with said input port means and adapted to extend thereto from a position located above a predetermined fluid level in said housing when said condenser assembly is functioning; and pressure equalization means extending between a gravitationally top region of said housing and said input conduit at said position, said pressure equalization means comprising a capillary tube.
 2. The condenser assembly of claim 1 wherein said wall member portions are affixed to outer wall regions of said housing means and comprise a plurality of elongated conduit means in spaced-apart relationship to each other adapted to extend generally normally to and outwardly from said interior chamber portion to interconnection with a second interior chamber portion located in and comprising said top region.
 3. The condenser assembly of claim 1 wherein said wall member portions comprise a plurality of tubular members in spaced relationship to each other and to outer wall regions of said housing means, said tubular members extending through said housing means interiorly thereof and adapted to convey therethrough said heat exchange fluid.
 4. The condenser assembly of claim 1 wherein said wall members extend vertically.
 5. The condenser assembly of claim 1 wherein said wall members extend horizontally.
 6. An air cooled condenser assembly adapted for use in a mechanical refrigeration system of the vapor compression type comprising A. a plurality of elongated conduit means in spaced relationship to each other, each adapted for heat transfer through side wall portions thereof, B. a pair of header means each one at a different opposed respective end portion of said plurality of conduit means and functionally interconnecting individual respective ends of said conduit, C. a distributor conduit extending through one of said header means, saiD conduit being perforated along its side walls and being in sealed engagement with the associated said header means at opposite ends thereof, one end of said distributor conduit defining an input port, D. an input conduit associated with said input port and adapted to extend thereto from a position located above a predetermined fluid level in said housing when said condenser assembly is functioning and said distributor conduit is in a gravitationally bottom region of said condenser assembly, E. pressure equalization means functionally extending between a gravitationally top region of said housing when said condenser assembly is functioning and said input conduit at said position, and F. output port means located in said associated said header means.
 7. A condenser assembly adapted for use in a mechanical refrigeration system of the vapor compression type, comprising: a fluid-tight housing means having defined therein an interior refrigerant chamber portion having gravitationally bottom and top regions; input port means and output port means located in said bottom region of said chamber; and wall member portions adapted for heat exchange therethrough when a heat-sink fluid contacts surfaces of said wall members opposite other surfaces contacting refrigerant communicating with said chamber; an input conduit communicating with said input port means and adapted to extend thereto from a position located above an operating fluid level in said housing; and a capillary tube constituting a pressure equalization means communicating with top region of said housing to said input conduit at said position.
 8. A condenser assembly as defined in claim 7, further defined by: said input port means comprising: surfaces defining an open well in said bottom portion of said housing, a nozzle situated at the opening of the well and directed into the refrigerant chamber, and said compressed gaseous refrigerant passing through said nozzle, thereby to be sub-cooled; and said output port means comprising a conduit communicating with said input port well at a point gravitationally beneath said well opening.
 9. A condenser assembly as defined in claim 7, wherein: said heat-sink fluid comprises a gas such as air; said refrigerant chamber comprises a pair of header portions; and said wall members define a plurality of elongate conduits having exteriors which contact said gas and interiors which communicate at opposite ends thereof with said refrigerant chamber headers and confine and carry said refrigerant in vapor and liquid forms.
 10. A condenser assembly as defined in claim 7, wherein: said heat-sink fluid comprises a liquid such as water; and said wall members define a plurality of elongate conduits extending through said refrigerant chamber and separating said refrigerant vapor and liquid on an exterior thereof and the interior thereof carrying said heat-sink liquid.
 11. An air cooled condenser assembly adapted for use in a mechanical refrigeration system of the vapor compression type, comprising: a plurality of elongate conduit means in spaced relationship to each other, each adapted for heat transfer through side wall portions thereof; first and second header means each at a different opposed respective end portion of said plurality of conduit means and interconnecting individual respective ends of said conduits; a distributor conduit extending into said first header means, said conduit being perforated along its side walls in a gravitationally bottom region of said condenser assembly and being in sealed engagement with said first header means; an input conduit communicating with said distributor conduit and adapted to extend thereto from a position located above a predetermined fluid level to said housing; pressure equalization means extending between a gravitationally top region of said second header means and said input conduit at said positiOn; and output port means. 